Chelating agents wastewater treatment

The previous sections have discussed the radiolytic decomposition of pollutants in water and wastewater. Other applications are possible. Chelating agents were often used in various processes designed to separate radionuclides at nuclear laboratories. The presence of these compounds in the resulting nuclear wastes complicates treatment. The radiolytic degradation of these compounds is an area of current investigation [39]. 

Most traditional chelating agents, however are poorly biodegradable. Some are actually quite persistent and do not adsorb at the surface of soils in the environment or at activated sludge in wastewater treatment plants. Because of this poor biodegradability combined with high water solubility, traditionally used chelators are readily released into the environment, and have been detected in the surface waters of rivers and lakes, and in make-up water processed for drinking water. 

Removal of lead from water is performed generally by precipitation as carbonate or hydroxide with or without coagulation. Chelation with EDTA, nitrilotriacetic acid, or other agents is another usual treatment followed by recovery using precipitation, electrolysis, or chemical oxidation (Borrell-Damian and Ollis, 1999). However, most of these treatments are expensive, and some other ways of lead elimination from wastewater are necessary to be developed. 

---